On Mar 7, 2011, at 8:25 PM, Milo Velimirović wrote:
> > On Mar 7, 2011, at 7:06 PM, Chris Murphy wrote: > >> >> On Mar 7, 2011, at 6:02 PM, Markus Hitter wrote: >> >>> >>> Am 07.03.2011 um 20:22 schrieb Chris Murphy: >>> >>>> I don't know the difference with XNU between block level and raw device >>> >>> For reading the whole thing, the result should be the same for both. A >>> "cmp", "diff" or two "md5" should tell you wether I'm speaking the truth ;-) >> >> >> I agree. Should be the same for both with respect to performance as well, >> but they aren't. 6x slower for block level compared to raw. > > Yes, the resulting files should be the same; no, the copy should not be the > same speed! It's hard for me to believe that this confusion about block vs. > character/raw devices still exists when UNIX is more than 40 years old. OK well, then it should be simple for you to explain why /dev/disk0 results in 17MB/s read, and /dev/rdisk0 results in 107MB/s read, and on Linux /dev/sda result in 107MB/s read which is the block level device and there is no raw device created anymore. Chris Murphy_______________________________________________ MacOSX-admin mailing list [email protected] http://www.omnigroup.com/mailman/listinfo/macosx-admin
